/*
 * Copyright (c) 2017 Baidu, Inc. All Rights Reserve.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.baidu.fsg.uid.utils;

import cn.hutool.core.util.StrUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * DockerUtils
 *
 * @author yutianbao
 */
public final class DockerUtils {
	private static final Logger LOGGER = LoggerFactory.getLogger(DockerUtils.class);
	/**
	 * Environment param keys
	 */
	private static final String ENV_KEY_HOST = "JPAAS_HOST";
	private static final String ENV_KEY_PORT = "JPAAS_HTTP_PORT";
	private static final String ENV_KEY_PORT_ORIGINAL = "JPAAS_HOST_PORT_8080";
	/**
	 * Docker host & port
	 */
	private static String DOCKER_HOST = "";
	private static String DOCKER_PORT = "";
	/**
	 * Whether is docker
	 */
	private static boolean IS_DOCKER;

	static {
		retrieveFromEnv();
	}

	private DockerUtils() {
	}

	/**
	 * Retrieve docker host
	 *
	 * @return empty string if not a docker
	 */
	public static String getDockerHost() {
		return DOCKER_HOST;
	}

	/**
	 * Retrieve docker port
	 *
	 * @return empty string if not a docker
	 */
	public static String getDockerPort() {
		return DOCKER_PORT;
	}

	/**
	 * Whether a docker
	 *
	 * @return 是否docker
	 */
	public static boolean isDocker() {
		return IS_DOCKER;
	}

	/**
	 * Retrieve host & port from environment
	 */
	private static void retrieveFromEnv() {
		// retrieve host & port from environment
		DOCKER_HOST = System.getenv(ENV_KEY_HOST);
		DOCKER_PORT = System.getenv(ENV_KEY_PORT);

		// not found from 'JPAAS_HTTP_PORT', then try to find from 'JPAAS_HOST_PORT_8080'
		if (StrUtil.isBlank(DOCKER_PORT)) {
			DOCKER_PORT = System.getenv(ENV_KEY_PORT_ORIGINAL);
		}

		boolean hasEnvHost = StrUtil.isNotBlank(DOCKER_HOST);
		boolean hasEnvPort = StrUtil.isNotBlank(DOCKER_PORT);

		// docker can find both host & port from environment
		if (hasEnvHost && hasEnvPort) {
			IS_DOCKER = true;

			// found nothing means not a docker, maybe an actual machine
		} else if (!hasEnvHost && !hasEnvPort) {
			IS_DOCKER = false;

		} else {
			LOGGER.error("Missing host or port from env for Docker. host:{}, port:{}", DOCKER_HOST, DOCKER_PORT);
			throw new RuntimeException(
				"Missing host or port from env for Docker. host:" + DOCKER_HOST + ", port:" + DOCKER_PORT);
		}
	}

}
